The invention relates to a method for transmitting data in a battery management system having at least one main control device and a number of module control devices which transmit measured values to the main control device via a communications channel.
The invention also relates to a computer program, a battery management system and a battery which are set up to carry out the method.
Electronic control devices are nowadays used in increasing numbers in the automotive sector. Examples are engine control devices and control devices for ABS or the airbag. For electrically driven vehicles, a contemporary research focus is the development of powerful battery packs with associated battery management systems, that is to say control devices which are equipped with software for monitoring the battery functionality. Battery management systems ensure, inter alia, the safe and reliable operation of the battery cells and battery packs used. They monitor and control currents, voltages, temperatures, insulation resistances and further variables for individual cells and/or the entire battery pack. Management functions which increase the service life, reliability and safety of the battery system can be implemented with the aid of these variables.
Battery management systems consist of a multiplicity of control devices on which individual software functionalities run. In this case, depending on the number of battery cells, the number of sensors and the distribution of the battery modules to different installation spaces in the vehicle, a control device topology having a main control device and a plurality of subordinate module control devices for recording the measurement data directly at the individual battery modules results. The recorded data are interchanged between the control devices via a communications channel. Measurement data are communicated at a high frequency to the main control device on the communications channel by using a large number of battery modules and associated module control devices. The measurement frequency is generally restricted by properties of the communications channel, for example a bandwidth on a data bus, and by the number of battery modules.
US 2010/0019732 A1 describes a battery management system having a main control device and a plurality of battery units, one battery unit determining a reference measured value which changes on the basis of predetermined criteria without the influence of the main control device.
KR10/0680901 shows a battery management system comprising a main control device and a plurality of module control devices, the module control devices determining and providing cell voltages and temperatures. The main control device makes it possible to carry out so-called battery balancing if a difference between the cell voltage and a reference measured value assumes a defined critical value.